Run mock inside rootless Podman container

This change will allow andaman to run on any distro, since all you need is podman and a base OCI image
```[tasklist]
### Tasks
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The issue names no files, tests, or entry points. Start by locating how andaman currently runs mock and identify the existing build or CI integration points. Done should mean mock runs inside a rootless Podman container using a base OCI image, but the issue does not define the required interface or validation steps.

Written by the indexing model from the issue text.